Generally the tip of a screwdriver or a similar tool is used for removing the lid from a tin, the tool being inserted under the lip of the lid and a levering action is used against the top edge of the tin. However, when any appreciable resistance to removal of the lid occurs, for example due to solidified paint, then there is a tendency for such levering to cause a deformation of the lid. This not only makes subsequent removal of the lid more difficult, but may also prevent proper closure of the tin when the lid is re-applied.
The problem becomes more acute with tins having lids of the type that have been introduced in recent years, particularly for larger sizes such as the 5 liter. With such tins, the lid when fitted in the factory is in tight sealing relationship with the tin and is resistant to unintentional removal for example under vibration and impact. This type of tin has a rim at the upper end which is turned over and downwardly to provide an inwardly projecting annular shelf below the height at the top of the rim, which then extends to a U shaped groove projecting downwardly relative to the axis of the tin. The lid of the tin similarly has a generally U shaped edge portion for engaging in the U shaped groove, and a laterally extending annular flange which is adapted essentially to seat against the shelf portion to limit the extent to which the lid is pressed onto the tin.